吸附模式对有机物光催化降解的影响1.H-酸在TiO2表面的吸附模式

H-酸萘环上含有的两个磺酸基团,在水溶液中可以解离一个或者两个.pH 2.5条件下,主要有一个磺酸基团解离,此时,H-酸通过一个磺酸基团吸附在TiO2表面,占位小,饱和吸附量大,但吸附键较弱,吸附较可逆.pH 5.0条件下,主要有两个磺酸基团解离,此时,H-酸通过两个磺酸基团吸附在TiO2表面,占位大,饱和吸附量小,但吸附键较强,吸附不可逆性较强.这种吸附模式的差异是导致H-酸在不同pH条件下饱和吸附量和吸附不可逆性差异的根本原因,也是导致不同pH条件下H-酸具有不同光催化降解途径的重要原因.     

资源利用中的不确定性、不可逆性分析

资源是社会经济持续发展的动力，也是人类赖以生存的基本条件。在资源开发和利用过程中人们对所存在的不确定性和不可逆性重视不够，从而使资源得不到合理的开发和利用甚至遭到破坏。本文分析了资源利用中的不确定性和不可逆性，为资源的合理开发做了探索性研究，为同行们更深入的研究这种不确定性问题起到一个引领的铺垫作用。     

Uncertainty,Irreversibility and the Timing Problems of Environmental Policy

Abstract

Most environmental issues and policy designing are uncertain and irreversible; therefore, the timing of environmental policy implementation becomes especially important. This paper establishes a random dynamic programming model and analyzes the optimal timing problems in environmental policy under uncertain variables. This model results indicate that two variables have a significant impact on the timing of environmental policy implementation and they work in opposite directions: on one hand, the more uncertain the economy is, the higher the cost of policies implementation will be, and consequently the incentive to immediately adopt the policy will be stronger. On the other hand, the higher the uncertainty of the environment is, the stronger the irreversibility of ecological harm caused by pollutants per unit will be. Therefore, the government should implement new environmental policies as early as possible in order to gain more ecological benefits.     

Comparative performance study of different configurations of organic Rankine cycle using low-grade waste heat for power generation

This paper aims at analyzing the feasibility of a waste heat recovery power generation plant based on parametric optimization and performance analysis using different organic Rankine cycle configurations and heat source temperature conditions with working fluid R-12, R-123, R-134a, and R-717. A parametric optimization of turbine inlet temperature(TIT) was performed to obtain the irreversibility rate, system efficiency, availability ratio, turbine work output, system mass flow rate, second-law efficiency, and turbine outlet quality, along the saturated vapor line and also on superheating at an inlet pressure of 2.50 MP in basic as well as regenerative organic Rankine cycle. The calculated results reveal that selection of a basic organic Rankine cycle using R-123 as working fluid gives the maximum system efficiency, turbine work output, second-law efficiency, availability ratio with minimum system irreversibility rate and system mass flow rate up to a TIT of 150°C and appears to be a choice system for generation of power by utilizing the flue gas waste heat of thermal power plants and above 150°C the regenerative superheat organic Rankine cycle configuration using R 123 as working fluid gives the same results.     

基于不确定性的矿区污染治理投入决策研究

基于现实的基础上,考虑矿区污染治理所面临的不确定性,对污染治理最优投入的政策决策机制进行研究.根据污染治理投入成本的不可逆性及不确定性建立污染治理最优投入决策机制模型,求出了污染治理投入的临界点.结果表明,该模型能够真实、客观、全面地评价矿区污染治理投入决策机制,并可动态指导治理政策实施的最优时机.同时,分析了模型中各参数对污染治理决策的影响,结合案例验证了此模型在污染治理决策问题上的分析结果.结果发现,考虑了不确定性的模型有效避免了传统决策模型的局限性,可以帮助政府和煤矿企业做出科学有效的污染治理投入决策和制度设计,能更有效地推动煤矿企业安全生产的实施.本研究对环境政策的制定和实施具有理论和实践指导意义.     

Particle concentration effect in adsorption/desorption of Zn（Ⅱ） on anatase type nano TiO2

Adsorption/desorption in a new Zn(II)-TiO2 adsorption system was investigated at different particle concentrations (Cp). TEM, SEM and XRD analyses revealed that the TiO2 particles were an aggregation of nano-sized (approximately 10 nm) pure anatase-type TiO2. Adsorption experiments were carried out with particle concentrations of 100, 400 and 1000 mg/L, and their adsorption isotherms were found to decline successively, showing an obvious Cp effect. Desorption experiments indicated that adsorption in this system was irreversible, and the irreversibility increased with increasing Cp. These phenomena could be explained by the MEA (metastable equilibrium adsorption) theory and the Cp effect could be modeled well with an MEA-Freundlich-type Cp effect isotherm equation. This study may help understand environmental behavior of contaminants on ultrafine natural particles.     

中国南方河流和湖泊沉积物对菲的吸附特性

采用循环吸附/解吸实验法,研究了西湖,滇池,太湖,甬江和钱塘江表层沉积物对菲的吸附特性.结果表明5水域沉积物对菲的吸附行为与沉积物有机碳含量有关,西湖和滇池沉积物对菲的吸附表现出明显不可逆性.研究发现当将总吸附量分解成可逆和不可逆吸附2个部分后,其可逆吸附部分可以很好地用脂/水分配机理进行预测.本工作认为河流和湖泊表层沉积物中的有机碳是控制菲环境行为的一个重要因素,但是其生态风险同时取决于沉积物的不可逆吸附特性.     

Uncertainty,Irreversibility and the Timing Problems of Environmental Policy

Most environmental issues and policy designing are uncertain and irreversible;therefore,the timing of environmental policy implementation becomes especially important.This paper establishes a random dynamic programming model and analyzes the optimal timing problems in environmental policy under uncertain variables.This model results indicate that two variables have a significant impact on the timing of environmental policy implementation and they work in opposite directions:on one hand,the more uncertain the economy is,the higher the cost of policies implementation will be,and consequently the incentive to immediately adopt the policy will be stronger.On the other hand,the higher the uncertainty of the environment is,the stronger the irreversibility of ecological harm caused by pollutants per unit will be.Therefore,the government should implement new environmental policies as early as possible in order to gain more ecological benefits.